Project Summary: Voice disorders affect 3 ? 9% of the U.S. population and cause devastating effects to communication, limiting occupational and social participation. Elevated laryngeal tension is a significant factor in a range of functional and neurological voice disorders and a crucial target of therapeutic intervention. Overall, disorders associated with increased laryngeal tension are highly prevalent, accounting for over 65% of referrals to multidisciplinary voice clinics. Current clinical assessment is primarily based on unreliable auditory impressions and manual palpation, since standard acoustic measures are not specific to laryngeal tension. To address this gap, we have proposed an acoustic estimate of laryngeal tension, relative fundamental frequency (RFF), which has shown promise across a range of voice disorders associated with laryngeal tension. Previously, the time required to manually estimate RFF has prevented its clinical application, but our newly developed open-source algorithms for automated RFF estimation now allow for the large-scale, fine-grained studies required to endorse clinical use of RFF as an objective measure of laryngeal tension. Our collaborative team of clinicians, scientists, and engineers will utilize our new automated algorithms to systematically validate RFF as a measure of laryngeal tension in two voice disorder populations that span age and etiology (functional vs. neurological): vocal hyperfunction and Parkinson's disease. Aim 1 will supply concurrent validity by comparing RFF to two objective estimates of laryngeal tension: 1) kinematic stiffness and 2) an acoustic-accelerometric ratio based on aerodynamic efficiency. Aim 2 will assess the ability of RFF to capture clinically meaningful changes in laryngeal tension, following expected changes in function that are both improving (post-therapy vocal hyperfunction) and worsening (disease progression in PD). The ability of RFF to capture these changes will be compared with that of the objective measures from Aim 1 as well as currently clinically viable measures (standard acoustic measures and auditory-perceptual judgments). These data are essential to support the use of RFF as a clinical outcome measure in future assessments of treatment efficacy. Finally, Aim 3 will determine the diagnostic sensitivity and specificity of RFF in a large cohort of speakers with and without tension-related voice disorders, allowing clinicians to meaningfully interpret RFF values of individual patients with respect to age, sex, and diagnosis. Overall, this project will provide the first-ever examination of the clinical utility of an acoustic measure of voice with this degree of comprehensive detail, power, and scope, feasible only within a framework of partnership between basic and clinical researchers. Successful completion will result in a fully validated, objective, and automated estimate of laryngeal tension. This non-invasive and inexpensive assessment can be translated immediately to clinical practice, facilitating evidence-based practice, targeted voice therapy, and the tracking of disease status across a range of voice disorders.